At present, with the development of the OTN and the continuous improvement of the OTN-relative standards, the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) provides the ODUflex. One kind of ODUflex in related art is the ODUflex (GFP) for bearing packet client signals. This technology encapsulates the packet client signals into the ODUflex (GFP) via the GFP. In this case, based on whether the rate is variable, the client signals are divided into the client signals with fixed bit rate and the client signals with variable bit rates.
The ODUflex (GFP) of the related art can have any rate. But at present, one ODUflex (GFP) is fixedly distributed with a large enough bandwidth, so as to make the ODUflex (GFP) completes transmission under the worst condition.
For example, the Ethernet Media Access Control (MAC) frame signals based on the 802.3 standards of Institute of Electrical and Electronics Engineers (IEEE) belong to the client signals with variable rates. The bandwidth request for the OTN is dynamically variable, and the frame length and frame gap are dynamically variable. Taking the example that an Optical channel Transport Unit (OTU) 3 bears 10 Gigabit Ethernet (10 GbE) MAC frame signals to transmit on the OTN network, the recent method includes: (1) implementing GFP encapsulation of frame mapping for the Ethernet MAC frame signals according to the possible maximum rate of the Ethernet MAC frame signals; (2) asynchronously mapping the signals which are implemented with GFP encapsulation to a low-order Optical channel Data Unit (ODU) 2. As the rate of the Ethernet MAC frame signals is continuously changed, a GFP idle frame needs to be inserted in the payload of the low-order ODU according to the change of the rate of the Ethernet MAC frame signals, so as to achieve the purpose of rate matching; and (3) multiplexing a plurality of low-order ODU2s to be a high-order ODU3. The high-order ODU3 forms the OTU3 signals to be transmitted in the OTN network after inserting the overhead. During the transmission process of the OTN, the number of Time Slot (TS) distributed to the low-order ODU2 is constant, that is, the occupied OTN network bandwidth is constant.
In a conclusion, the bandwidth of the packet client signals is variable along the time, but the redundant bandwidth which is distributed to the ODUflex (GFP) is constant, thereby the waste of bandwidth resource is caused.